A navigation system for use in a motor vehicle generally includes a computer having a microprocessor and memory storing a digital road map. The navigation system may also include a screen, on which a map section with a current position can be displayed. The size of the map section may be selected using an adjustable image scale. Moreover, a corresponding section of a route from the current position to a specified destination may be displayed on the map section when a route guidance is active.
The map section may also be displayed on the screen in various display modes, e.g. in a three-dimensional (3-D) perspective view, which shows a bird's-eye view in the direction of motion, or in a two-dimensional (2-D) display in a plan view onto a map section. Such a 2-D map section may be displayed north-pointing or direction-pointing on the screen.
In the case of a direction-pointing display, the digital road map around the current position is continuously orientated in the direction of motion. In other words, the direction of motion in the display on the screen is always orientated in the direction of an upper edge. The current position is indicated for example with an arrow-shaped cursor. The tip of the arrow marks the direction of travel, which in the case of the direction-pointing display always points in the direction of the upper edge of the map section or of the screen. The arrow-shaped cursor is arranged for example in the vertical direction in the lower half of the map section, preferably at the lower edge. The cursor is preferably centered horizontally with respect to the map section.
In the case of a north-pointing display, the geographical north of the digital road map is always orientated towards the upper edge of the screen display. The current position can be marked with an arrow-shaped cursor on the displayed map section, which cursor is continuously orientated in the direction of travel and thus indicates the current direction of travel on the screen. In the case of the north-pointing display, the arrow-shaped cursor, which marks the current position on the digital road map, is held in a fixed position, preferably in the center of the map section displayed on the screen. If a route guidance to a specified destination is active, a section of the corresponding planned route is displayed on the displayed map section. The planned route arises in the center of the displayed map section. Depending on the set map scale, which determines the size of the displayed map section, the displayed section of the planned route may run out of the displayed map section in one direction. This is usually the case especially with small map scales, i.e. with a detailed display of the digital road map on the screen.
In the case of the north-pointing display of a digital road map with a planned route on a screen of a navigation system, the route section from the center-point of the screen display often runs directly to the edge of an image of the display in one direction. This means that, in the case of the north-pointing display, only a small proportion of the available display area on the screen or the map section is used to display the route ahead. The vehicle driver thus also receives only limited information concerning the route ahead.
Accordingly, there is a need in the art to provide an improved north-pointing display of a digital road map with a planned route such that more information concerning the route ahead is displayed.